diff --git a/subjects/login/README.md b/subjects/login/README.md new file mode 100644 index 00000000..22cc8c6f --- /dev/null +++ b/subjects/login/README.md @@ -0,0 +1,54 @@ +## Console + +### Login + +![TRON: Legacy](tron.jpg) + +> In the movie _TRON: Legacy_, Linux is rebranded "SolarOS" in reference to [Solaris](), another Unix OS + +--- + +Start the VM to boot the previously installed Debian system. + +Do the following for both a user and the [superuser](https://en.wikipedia.org/wiki/Superuser) (`root`) : + +- Log in +- Clear the console using the keyboard shortcut +- Change the password to a space : `" "` +- Show the command history using five keystrokes or less (using autocompletion) +- Log out using the keyboard shortcut + +### Just numbers + +Login as [`root`](https://en.wikipedia.org/wiki/Superuser) on the third [Linux console](https://en.wikipedia.org/wiki/Linux_console). + +Check the Internet connectivity with the command `ping google.com`. +After a few hops, interrupt the program with : Ctrl + C. + +Behind every name in a computer system there is a number (ID, index, address, etc) : + +- User identifier + - `root` → `0` + - `student` → `1000` +- IP address + - google.com → 216.58.214.14 (quad-dotted notation) → `3627734542` + - tencent.com → 117.169.101.44 (quad-dotted notation) → `1974035756` +- File inode + - `/etc/fstab` → `44696029` + - `.profile` → `59639363` +- Port + - `HTTP` → `80` + - `HTTPS` → `443` +- Process identifier + - `cron` → `254` + +Names exist because they are human readable, but behind the scenes they are converted into numbers, unique in their namespace : + +- A domain name can have several IP addresses, but an IP address can only identify one domain name +- Several processes may have the same name, but a PID identifies a single process + +Find the commands to get : + +- the inode of a specific file +- the current user ID +- the PID of a program, for example `bash` diff --git a/subjects/login/tron.jpg b/subjects/login/tron.jpg new file mode 100644 index 00000000..0db8ea33 Binary files /dev/null and b/subjects/login/tron.jpg differ